Early Theories
There has been a long history of confusion regarding the efficacy of various therapeutic regimens, a fact that has often led to the success of disreputable physicians:
a) many patients improve spontaneously no matter what the therapy,
b) up to one third will feel better by placebo effect alone, and
c) the therapist's convincing conclusion that a bad outcome resulted from the patient's sinful behavior or tardiness in seeking medical help.